(2)The expenditure referred to in sub-section (1) is that incurred by the assessee after the date specified in that sub-section at any time during the year of commercial production and any one or more of the four years immediately preceding that year, wholly and exclusively on any operations relating to prospecting for any mineral or group of associated minerals specified in Part A or Part B, respectively, of the Seventh Schedule or on the development of a mine or other natural deposit of any such mineral or group of associated minerals:Provided that there shall be excluded from such expenditure any portion thereof which is met directly or indirectly by any other person or authority and any sale, salvage, compensation or insurance moneys realised by the assessee in respect of any property or rights brought into existence as a result of the expenditure.
